New mail icon in tray

There are two ways to show new mail notification; Windows Action Center and eM Client’s own notifications.

You can change the settings in Menu > Tools > Settings > General > Notifications. 

If you tick  Use system notifications , they will be passed on to the Windows Action Center, and you can configure that in your Windows 10 settings.

If you untick that, you will get the traditional new mail icon. You may also have to change your Windows Taskbar settings to show the eM Client mail notification.